Kμ3Branching Ratio andμ+Energy Spectrum

Abstract

The muon energy spectrum of $K_{\mu 3}$ decay was studied in heavy liquid and ${\mathrm{H}}_2$ bubble chambers. The results favor vector coupling with a small negative value of the real part of the ratio $\xi$ of the two vector form factors. The $K_{\mu 3}$ branching ratio obtained is 3.45±0.20%.